CA1253726A - Polarization rotation compensator and optical isolator using the same - Google Patents
Polarization rotation compensator and optical isolator using the sameInfo
- Publication number
- CA1253726A CA1253726A CA000430872A CA430872A CA1253726A CA 1253726 A CA1253726 A CA 1253726A CA 000430872 A CA000430872 A CA 000430872A CA 430872 A CA430872 A CA 430872A CA 1253726 A CA1253726 A CA 1253726A
- Authority
- CA
- Canada
- Prior art keywords
- incident light
- compensator
- plane
- wavelength
- rotator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/09—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on magneto-optical elements, e.g. exhibiting Faraday effect
- G02F1/093—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on magneto-optical elements, e.g. exhibiting Faraday effect used as non-reciprocal devices, e.g. optical isolators, circulators
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3083—Birefringent or phase retarding elements
Abstract
POLARIZATION ROTATION COMPENSATOR AND OPTICAL
ISOLATOR USING THE SAME
ABSTRACT OF THE DISCLOSURE
A polarization rotation compensator and an optical isolator using the same are described. The optical isolator comprises a first birefringent wedge plate; a polarization rota ion compensator composed of a combina-tion of a half-wave plate whose principal axis is inclined at an angle of .theta./2 with respect to the plane of polarization of the incident light and a quarter-wave plate whose principal axis is inclined at an angle of .theta.
with respect to the plane of polarization of the incident light; a Faraday rotator; and a second bire-fringent wedge plate, the Faraday rotator, quarter wavelength plate, and half-wavelength being arranged in the order of propagation of the backward light or forward light.
ISOLATOR USING THE SAME
ABSTRACT OF THE DISCLOSURE
A polarization rotation compensator and an optical isolator using the same are described. The optical isolator comprises a first birefringent wedge plate; a polarization rota ion compensator composed of a combina-tion of a half-wave plate whose principal axis is inclined at an angle of .theta./2 with respect to the plane of polarization of the incident light and a quarter-wave plate whose principal axis is inclined at an angle of .theta.
with respect to the plane of polarization of the incident light; a Faraday rotator; and a second bire-fringent wedge plate, the Faraday rotator, quarter wavelength plate, and half-wavelength being arranged in the order of propagation of the backward light or forward light.
Description
~2~3~7;~
-- 1 ~
POL~RIZATION ROTATION CO~l~ENSATOR AND OPTICAL
.
O~ r BACKGROUND OF THE INVENTION
Field of -the Invention The present invention relates to a polarization rotation compensator and to an optical isolator using the polarization rotation compensator. More partlcu-larly, it relates to a polarization rotation compensator which is capable of rotating a plane of polarization by a desired angle when linear polarization is passed therethrough and capable also of compensating for deviations in the polarizing angle due to deviations of the optical wavelength chanye in incident ray, and to an optical isolator which is not dependent on the wavelength change in incident ray.
Description of the Prior Art As is well known, a polarizer used in an optical device such as an isolator for optical communication at a wavelength of 1.30 ~m (microns), for e~ample, has a wavelength dependency. In an optical isolator, for example, when linear polarized light passes through a 45-degree Faraday rotator, a plane of polarization rotated 45 degrees about the direction of propagation thereof can be obtained. ~owever, this is possible only for light having a predetermined wavelength.
Deviation in the wavelength of the light causes the polarizing angle of the plane of polarization to deviate, resulting in deterioration of the isolation effect of the isolator.
Crystal quartz polarization rotation compensator which correct deviations in the optical rotating angle of a plane of polarization due to wavelength devia-tions are well known in the art.
However, although crystal quartz polarization rotation compensator whose principal a~is is parallel lZS3~
to the propagating light can correct devi.ations in the optical rotating angle, they are large, having a length, for example, of 10 mm to 15 mm along the optical axis when they are used for the long wavelength.
SUMMARY OF TEIE INVENTION
In accordance with one particular aspect of the present invention, there is provided a device comprising:
a compensator which includes a half-wave plate and a quarter-wave plate arranged in a predetermined order with respect to a beam of plane-polarized incident light, the respective orientations of the principal a~es of the plates with respect to the plane of polarization of the incident light being 0/~ and ~, the incident li.ght being incident first on the half-wave plate, and a rotator arranged in combination with the compensator, after the compensator with respect to the incident light, the rotator rotating the light passing therethrough by an amount that depends on wavelength, wherein ~ is provided at an optimum angle to compensate the wavelength dependency of the rotator in the predetermined wavelength region, thus a plane-polarized output beam is provided from the compensator with a rotation of the plane of polarization ~rom that of the incident light that depends on wavelength, and the rotation of the plane of polarization of the incident light, by the combination of the compensator and rotator, becomes independent of wavelength.
In accordance with another particular aspect of the present invention, there is provided a device comprising:
a compensator which includes a half-wave plate and a quarter-wave plate arranged in a predetermined order with respect -to a beam of plane-polarized incident light, the li~S;~7Z6 .
respective orientations oP the principal axes of the plates with respect to the plane Oe polarization oE the incident light being ~ and ~/2, the incident light being incident first on the quarter-wave plate, and a rotator arranged in a combination with the compensator, before the compensator with respect to the incident light, the rotator rotating the light passing therethrough by an amount that depends on wavelength, wherein a plane-polarized output beam is provided from the compensator with a rotation of the plane of polarization from that of the incident light that depends on wavelength in accordance with each value for ~ and the rotation of the plane of polarization of the incident light, by the combination of the compensator and rotator, becomes independent of wavelength.
BRIEF DESCRIPTION OF THE DRA~INGS
Further advantages and details of the present invention wlll become apparent through reference to the accompanying drawings, in which:
Figs. lA and lB are cross-sectional views of a conventional isolator;
Fig. 2 is a graph of the wavelength (~m) in relation to the isolation (dB) and polarization rotation (deg);
Fig. 3 is a perspective view of an example of a polarization rotation compensator according to the present invention;
Fig. 4 is a diagram of the principle of operation of the polarization rotation compensator sho~n in Fig. 3 using a Poincare sphere; and Figs. 5A, 5B and 5C are schematic views of an example of an isolator according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Before explaining the preferred embodiments of the invention, a description will be made of the prior art for reference.
1;~5;~7Z~
. .
An isolator using tapered birefringent wed~es, as shown in Figs. lA and lB have previously been proposed in U.S. Serial No. 329940. In F'igs. lA and lB, birefringent wedges la and lb are placed at the front and back oE a Faraday rotator 2, consisting of a single crystal of yttrium-iron-garnet (YIG). The birefringent wedge la refxacts the ordinary and the extraordinary rays 3a and 3b at different angles. The Faraday rotator
-- 1 ~
POL~RIZATION ROTATION CO~l~ENSATOR AND OPTICAL
.
O~ r BACKGROUND OF THE INVENTION
Field of -the Invention The present invention relates to a polarization rotation compensator and to an optical isolator using the polarization rotation compensator. More partlcu-larly, it relates to a polarization rotation compensator which is capable of rotating a plane of polarization by a desired angle when linear polarization is passed therethrough and capable also of compensating for deviations in the polarizing angle due to deviations of the optical wavelength chanye in incident ray, and to an optical isolator which is not dependent on the wavelength change in incident ray.
Description of the Prior Art As is well known, a polarizer used in an optical device such as an isolator for optical communication at a wavelength of 1.30 ~m (microns), for e~ample, has a wavelength dependency. In an optical isolator, for example, when linear polarized light passes through a 45-degree Faraday rotator, a plane of polarization rotated 45 degrees about the direction of propagation thereof can be obtained. ~owever, this is possible only for light having a predetermined wavelength.
Deviation in the wavelength of the light causes the polarizing angle of the plane of polarization to deviate, resulting in deterioration of the isolation effect of the isolator.
Crystal quartz polarization rotation compensator which correct deviations in the optical rotating angle of a plane of polarization due to wavelength devia-tions are well known in the art.
However, although crystal quartz polarization rotation compensator whose principal a~is is parallel lZS3~
to the propagating light can correct devi.ations in the optical rotating angle, they are large, having a length, for example, of 10 mm to 15 mm along the optical axis when they are used for the long wavelength.
SUMMARY OF TEIE INVENTION
In accordance with one particular aspect of the present invention, there is provided a device comprising:
a compensator which includes a half-wave plate and a quarter-wave plate arranged in a predetermined order with respect to a beam of plane-polarized incident light, the respective orientations of the principal a~es of the plates with respect to the plane of polarization of the incident light being 0/~ and ~, the incident li.ght being incident first on the half-wave plate, and a rotator arranged in combination with the compensator, after the compensator with respect to the incident light, the rotator rotating the light passing therethrough by an amount that depends on wavelength, wherein ~ is provided at an optimum angle to compensate the wavelength dependency of the rotator in the predetermined wavelength region, thus a plane-polarized output beam is provided from the compensator with a rotation of the plane of polarization ~rom that of the incident light that depends on wavelength, and the rotation of the plane of polarization of the incident light, by the combination of the compensator and rotator, becomes independent of wavelength.
In accordance with another particular aspect of the present invention, there is provided a device comprising:
a compensator which includes a half-wave plate and a quarter-wave plate arranged in a predetermined order with respect -to a beam of plane-polarized incident light, the li~S;~7Z6 .
respective orientations oP the principal axes of the plates with respect to the plane Oe polarization oE the incident light being ~ and ~/2, the incident light being incident first on the quarter-wave plate, and a rotator arranged in a combination with the compensator, before the compensator with respect to the incident light, the rotator rotating the light passing therethrough by an amount that depends on wavelength, wherein a plane-polarized output beam is provided from the compensator with a rotation of the plane of polarization from that of the incident light that depends on wavelength in accordance with each value for ~ and the rotation of the plane of polarization of the incident light, by the combination of the compensator and rotator, becomes independent of wavelength.
BRIEF DESCRIPTION OF THE DRA~INGS
Further advantages and details of the present invention wlll become apparent through reference to the accompanying drawings, in which:
Figs. lA and lB are cross-sectional views of a conventional isolator;
Fig. 2 is a graph of the wavelength (~m) in relation to the isolation (dB) and polarization rotation (deg);
Fig. 3 is a perspective view of an example of a polarization rotation compensator according to the present invention;
Fig. 4 is a diagram of the principle of operation of the polarization rotation compensator sho~n in Fig. 3 using a Poincare sphere; and Figs. 5A, 5B and 5C are schematic views of an example of an isolator according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Before explaining the preferred embodiments of the invention, a description will be made of the prior art for reference.
1;~5;~7Z~
. .
An isolator using tapered birefringent wed~es, as shown in Figs. lA and lB have previously been proposed in U.S. Serial No. 329940. In F'igs. lA and lB, birefringent wedges la and lb are placed at the front and back oE a Faraday rotator 2, consisting of a single crystal of yttrium-iron-garnet (YIG). The birefringent wedge la refxacts the ordinary and the extraordinary rays 3a and 3b at different angles. The Faraday rotator
2 rotates the plane of polarization 45 degrees. Since the Faraday rotation is dependent on the wavelength of the incident light, the wavelength region over which 45-degree rotation can be obtained is very narrow.
As shown in Fig. 2, the isolation is highest at a wavelength of 1.3 ~m when Faraday rotator (YIG) is adjusted such that ~he polarization is rotated 45 degrees at a wavelength of 1.3 ~m (a). When the wavelength is shorter or longer than 1.3 ~m, the isolation level rapidly decreases.
Fig. 3 shows an example of a polarization rotation compensator according to the present invention when the compensator is arranged at the front of the Faraday rotator. The compensator comprises a half-wave plate 15a and a quarter-wave plate 15b. The half-wave plate 15a is inclined at an angle of Q/2, and the quarter-wave plate 15b is inclined at an angle of ~, with respect to the vertical axis 16.
The principle of operation of the polarization rotation compensator can be illustrated by the Poincare sphere 17 shown in Fig. 4. In the Poincare spherical expression, linearly polarized light is indicated by the meridian, circularly polarized light is indicated by the poles, and elliptically polarized light is indicated by the another part of the spherical surface. Incident linear polarization having a wavelength of 1.4 ~m is transformed from the P0 state to the Q state by the hal~-wave plate 15a, whose principal axis lies in the H
direction i.e., the angle between the principal axis 1~3~7Z~;
and the polarization plane o-~ the incident light is ~/2 degree. The polariza~ion plane of the incident light is transformecl ~ degree b~ the halE-wave plate. When the wavelength of the inciden-t light deviates Erom 1.4 ~m, the state is distributed on the Pl according to the wavelengths. The polarization is transformed into state P2 by the ~uarter-wave plate 15b, whose principal axis lies in the Q-direction i.e., -the angle between the principal axis and the polarization plane of the incident light is 0.
Consequently, nearly linear polarization is passed through the polarization rotation compensator. Any deviation of the polarization rotation from 45 degrees is proportional to the deviation of the wavelength from 1.4 ~m.
Figures 5A, 5B and 5C show an example of an optical isolator for use with single-mode fibers and Figure 5C
shows another arrangement. This isolator comprises a first birefringent wedge lla, the abovementioned polarization rotation compensator composed of the half-wave plate 15a and the quarter-wave plate 15b, a Faraday rotator consisting, for example, of a single crystal of YIG, and a second birefringent wedge llb. The first and second birefringent wedges lla, llb together form a polarizing component. The present optical isolator is designed to maintain a high isolation over a wavelength region of 1.3 ~m to 1.5~m. Accordingly, all components are designed with a center wavelength of 1.4 ~m.
The isolator shown in Figure 5A works as follows.
Incident light from a fiber 19 enters the birefringent wedge lla through a lens 18. The birefringeDt wedge lla refracts the ordinary ray 13a and the extraordinary ray 13b at different angles, following which these pass through the above-described polarization ro-tation compensator composed of the half-wave plate 15a whose principal a~is is inclined at an angle of ~/2 with respect to the plane of polarization of the incident 12S3~
light, and the quarter-wave plate 15b whose principal axis is inclined at an angle of ~with respect -to plane of polarization oE the incident light,each Eormed Erorn a single quar-tz crystal, and on to the Faraday rotator 12.
The E~araday rotator 12 rotates the plane of polarization ~5 degrees. Since the Faraday rotation depends on the wavelength, the wavelength region that gives 45-degree rotation is very narrow. This makes it possible to maintain a high isolation only in a very limited wavelength region, unless deviation Erom 45-degree rotation is compensated for. A polarization ro-tation compensator is used in the present isolator in order to broaden the wavelength region over which a high isolation can be maintained. ~fter passing through the Faraday rotator 12, the ordinary and extraordinary rays enter the second birefringent wedge llb, through which they pass parallel to each other. They are then condensed to the left-hand fiber 19 through the left-hand lens 18.
As explained above, in Figs. 3 and 4, nearly linearly polarized light is passed through the polarization rotation compensator, and the deviation of the polari~ation rotation from 45 degrees i8 proportional to the wavelength deviation from 1.4 ~Im.
These deviations in the polarization rotation are summed ror the forward light and cancelled for the backward light. However, low forward loss is maintained in the broad wavelength region, as the ~orward loss is insensitive to the polarization rotation.
When the light propagates in the forward direction (from the left to the right in Fig. 5~), the ordinary and extraordinary rays in the left birefringent wedge lla are respectively transformed into ordinary and extraordinary rays by the right birefringent wedge llb and refraction by these wedges are cancelled out. On the other hand, when the light propagates in the backward direction as shown in Figure 5B~ the ordinary and extraordinary rays at the right bireEringent wedge ` :~;253~72~;
~ 7 -llb are respectively transformed into the extraordinary and ordinary rays at the left birefringent wedge lla, and reEractions by these wedges are not cance]led out.
The present optical isolator gives an improved isolation, as shown in Fig. 6. Namely, hiyh isolation of appro~imately 40 dB can be obtained for backward light in the wavelength region o 1.3 to 1.5 m. An isolation value of 40 dB could previously be obtained only at a wavelength o 1~3 m, as shown in Fig. 2.
The present isolator therefore is no-t dependent upon the wavelength. As explained above, the present polarization rotation compensator is composed of two coupled wavelength plates having thicknesses of 30 to lO0 ~m and diameters of 3 to 5mm, enabling the sizes o the compensator and the present optical isolator to be reduced.
It is preferable that the half-wave plate and quarter-wave plate each be ormed rom a single quartz crystal. The polarization rotation compensator should preferably range rom 30 ~m to lO0 ~m in thickness, and from 3 mm to 5 mm in diameter.
Furthermore, it is desirable that the first and second birefringent wedges be made of rutil or calcite, and that the Faraday rotator be made of YIG or paramagnetic glass.
,. - :: '''' ~ .
As shown in Fig. 2, the isolation is highest at a wavelength of 1.3 ~m when Faraday rotator (YIG) is adjusted such that ~he polarization is rotated 45 degrees at a wavelength of 1.3 ~m (a). When the wavelength is shorter or longer than 1.3 ~m, the isolation level rapidly decreases.
Fig. 3 shows an example of a polarization rotation compensator according to the present invention when the compensator is arranged at the front of the Faraday rotator. The compensator comprises a half-wave plate 15a and a quarter-wave plate 15b. The half-wave plate 15a is inclined at an angle of Q/2, and the quarter-wave plate 15b is inclined at an angle of ~, with respect to the vertical axis 16.
The principle of operation of the polarization rotation compensator can be illustrated by the Poincare sphere 17 shown in Fig. 4. In the Poincare spherical expression, linearly polarized light is indicated by the meridian, circularly polarized light is indicated by the poles, and elliptically polarized light is indicated by the another part of the spherical surface. Incident linear polarization having a wavelength of 1.4 ~m is transformed from the P0 state to the Q state by the hal~-wave plate 15a, whose principal axis lies in the H
direction i.e., the angle between the principal axis 1~3~7Z~;
and the polarization plane o-~ the incident light is ~/2 degree. The polariza~ion plane of the incident light is transformecl ~ degree b~ the halE-wave plate. When the wavelength of the inciden-t light deviates Erom 1.4 ~m, the state is distributed on the Pl according to the wavelengths. The polarization is transformed into state P2 by the ~uarter-wave plate 15b, whose principal axis lies in the Q-direction i.e., -the angle between the principal axis and the polarization plane of the incident light is 0.
Consequently, nearly linear polarization is passed through the polarization rotation compensator. Any deviation of the polarization rotation from 45 degrees is proportional to the deviation of the wavelength from 1.4 ~m.
Figures 5A, 5B and 5C show an example of an optical isolator for use with single-mode fibers and Figure 5C
shows another arrangement. This isolator comprises a first birefringent wedge lla, the abovementioned polarization rotation compensator composed of the half-wave plate 15a and the quarter-wave plate 15b, a Faraday rotator consisting, for example, of a single crystal of YIG, and a second birefringent wedge llb. The first and second birefringent wedges lla, llb together form a polarizing component. The present optical isolator is designed to maintain a high isolation over a wavelength region of 1.3 ~m to 1.5~m. Accordingly, all components are designed with a center wavelength of 1.4 ~m.
The isolator shown in Figure 5A works as follows.
Incident light from a fiber 19 enters the birefringent wedge lla through a lens 18. The birefringeDt wedge lla refracts the ordinary ray 13a and the extraordinary ray 13b at different angles, following which these pass through the above-described polarization ro-tation compensator composed of the half-wave plate 15a whose principal a~is is inclined at an angle of ~/2 with respect to the plane of polarization of the incident 12S3~
light, and the quarter-wave plate 15b whose principal axis is inclined at an angle of ~with respect -to plane of polarization oE the incident light,each Eormed Erorn a single quar-tz crystal, and on to the Faraday rotator 12.
The E~araday rotator 12 rotates the plane of polarization ~5 degrees. Since the Faraday rotation depends on the wavelength, the wavelength region that gives 45-degree rotation is very narrow. This makes it possible to maintain a high isolation only in a very limited wavelength region, unless deviation Erom 45-degree rotation is compensated for. A polarization ro-tation compensator is used in the present isolator in order to broaden the wavelength region over which a high isolation can be maintained. ~fter passing through the Faraday rotator 12, the ordinary and extraordinary rays enter the second birefringent wedge llb, through which they pass parallel to each other. They are then condensed to the left-hand fiber 19 through the left-hand lens 18.
As explained above, in Figs. 3 and 4, nearly linearly polarized light is passed through the polarization rotation compensator, and the deviation of the polari~ation rotation from 45 degrees i8 proportional to the wavelength deviation from 1.4 ~Im.
These deviations in the polarization rotation are summed ror the forward light and cancelled for the backward light. However, low forward loss is maintained in the broad wavelength region, as the ~orward loss is insensitive to the polarization rotation.
When the light propagates in the forward direction (from the left to the right in Fig. 5~), the ordinary and extraordinary rays in the left birefringent wedge lla are respectively transformed into ordinary and extraordinary rays by the right birefringent wedge llb and refraction by these wedges are cancelled out. On the other hand, when the light propagates in the backward direction as shown in Figure 5B~ the ordinary and extraordinary rays at the right bireEringent wedge ` :~;253~72~;
~ 7 -llb are respectively transformed into the extraordinary and ordinary rays at the left birefringent wedge lla, and reEractions by these wedges are not cance]led out.
The present optical isolator gives an improved isolation, as shown in Fig. 6. Namely, hiyh isolation of appro~imately 40 dB can be obtained for backward light in the wavelength region o 1.3 to 1.5 m. An isolation value of 40 dB could previously be obtained only at a wavelength o 1~3 m, as shown in Fig. 2.
The present isolator therefore is no-t dependent upon the wavelength. As explained above, the present polarization rotation compensator is composed of two coupled wavelength plates having thicknesses of 30 to lO0 ~m and diameters of 3 to 5mm, enabling the sizes o the compensator and the present optical isolator to be reduced.
It is preferable that the half-wave plate and quarter-wave plate each be ormed rom a single quartz crystal. The polarization rotation compensator should preferably range rom 30 ~m to lO0 ~m in thickness, and from 3 mm to 5 mm in diameter.
Furthermore, it is desirable that the first and second birefringent wedges be made of rutil or calcite, and that the Faraday rotator be made of YIG or paramagnetic glass.
,. - :: '''' ~ .
Claims (13)
1. A device comprising:
a compensator which includes a half-wave plate and a quarter-wave plate arranged in a predetermined order with respect to a beam of plane-polarized incident light, the respective orientations of the principal axes of said plates with respect to the plane of polarization of said incident light being .theta./2 and 6, said incident light being incident first on said half-wave plate, and a rotator arranged in combination with said compensator, after said compensator with respect to said incident light, said rotator rotating the light passing therethrough by an amount that depends on wavelength, wherein .theta. is provided at an optimum angle to compensate the wavelength dependency of said rotator in the predetermined wavelength region, thus a plane-polarized output beam is provided from said compensator with a rotation of the plane of polarization from that of said incident light that depends on wavelength, and the rotation of the plane of polarization of said incident light, by the combination of said compensator and rotator, becomes independent of wavelength.
a compensator which includes a half-wave plate and a quarter-wave plate arranged in a predetermined order with respect to a beam of plane-polarized incident light, the respective orientations of the principal axes of said plates with respect to the plane of polarization of said incident light being .theta./2 and 6, said incident light being incident first on said half-wave plate, and a rotator arranged in combination with said compensator, after said compensator with respect to said incident light, said rotator rotating the light passing therethrough by an amount that depends on wavelength, wherein .theta. is provided at an optimum angle to compensate the wavelength dependency of said rotator in the predetermined wavelength region, thus a plane-polarized output beam is provided from said compensator with a rotation of the plane of polarization from that of said incident light that depends on wavelength, and the rotation of the plane of polarization of said incident light, by the combination of said compensator and rotator, becomes independent of wavelength.
2. A device comprising:
a compensator which includes a half-wave plate and a quarter-wave plate arranged in a predetermined order with respect to a beam of plane-polarized incident light, the respective orientations of the principal axes of said plates with respect to the plane of polarization of said incident light being .theta. and .theta./2, said incident light being incident first on said quarter-wave plate, and a rotator arranged in a combination with said compensator, before said compensator with respect to said incident light, said rotator rotating the light passing therethrough by an amount that depends on wavelength, wherein a plane-polarized output beam is provided from said compensator with a rotation of the plane of polarization from that of said incident light that depends on wavelength in accordance with each value for .theta., and the rotation of the plane of polarization of said incident light, by the combination of said compensator and rotator, becomes independent of wavelength.
a compensator which includes a half-wave plate and a quarter-wave plate arranged in a predetermined order with respect to a beam of plane-polarized incident light, the respective orientations of the principal axes of said plates with respect to the plane of polarization of said incident light being .theta. and .theta./2, said incident light being incident first on said quarter-wave plate, and a rotator arranged in a combination with said compensator, before said compensator with respect to said incident light, said rotator rotating the light passing therethrough by an amount that depends on wavelength, wherein a plane-polarized output beam is provided from said compensator with a rotation of the plane of polarization from that of said incident light that depends on wavelength in accordance with each value for .theta., and the rotation of the plane of polarization of said incident light, by the combination of said compensator and rotator, becomes independent of wavelength.
3. The device of claim 1, comprising:
a pair of birefringent wedges arranged with said compensator and rotator therebetween, wherein respective refractions of said incident light by said pair of birefringent wedges cancel each other so that beams corresponding to ordinary and extraordinary rays of said incident light in each of said birefringent wedges are output in parallel, whereas respective refractions of said rays of light travelling in a direction opposite to said incident light do not cancel and are output in different directions.
a pair of birefringent wedges arranged with said compensator and rotator therebetween, wherein respective refractions of said incident light by said pair of birefringent wedges cancel each other so that beams corresponding to ordinary and extraordinary rays of said incident light in each of said birefringent wedges are output in parallel, whereas respective refractions of said rays of light travelling in a direction opposite to said incident light do not cancel and are output in different directions.
4. The device of claim 2, comprising:
a pair of birefringent wedges arranged with said compensator and rotator therebetween, wherein respective refractions of said incident light by said pair of birefringent wedges cancel each other so that beams corresponding to ordinary and extraordinary rays of said incident light in each of said birefringent wedges are output in parallel whereas respective refractions of said rays of light travelling in a direction opposite to said incident light do not cancel and are output in different directions.
a pair of birefringent wedges arranged with said compensator and rotator therebetween, wherein respective refractions of said incident light by said pair of birefringent wedges cancel each other so that beams corresponding to ordinary and extraordinary rays of said incident light in each of said birefringent wedges are output in parallel whereas respective refractions of said rays of light travelling in a direction opposite to said incident light do not cancel and are output in different directions.
5. The device of claim 3 or 4, comprising a pair of lenses combined with the combination of said compensator, rotator and wedges therebetween, wherein said rays corresponding to said incident light are focused to the same point in the light corresponding to said incident light that is output from the combination including said lenses, whereas the respective rays of the light travelling in said opposite direction from said incident light are focused at different respective points by said combination including said lenses.
6. The device of claim 3 or 4, wherein the wedges are of rutile or calcite.
7. The device of claim 1 or 2, said rotator being a Faraday rotator.
8. The device of claim 1 or 2, wherein said quarter-wave and half-wave plates are made of single-crystalline quartz.
9. The device of claim 1 or 2, wherein the thickness of said compensator is in the range from 30 to 100 microns.
10. The device of claim 1 or 2, wherein the diameter of said compensator is in the range from 3 to 5 mm.
11. The device of claim 1, wherein the dependency of said rotation provided by said compensator to said plane-polarized incident light is over a range including 1.3 to 1.5 microns.
12. The device of claim 2, wherein the dependency of said rotation provided by said compensator to said plane-polarized incident light is over a range including 1.3 to 1.5 microns.
13. The device of claim 11 or 12, wherein the change of said rotation provided by said compensator is proportional to deviation of the wavelength from 1.4 microns.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11101382A JPS592010A (en) | 1982-06-28 | 1982-06-28 | Optical rotator |
| JP57-109912 | 1982-06-28 | ||
| JP57-111013 | 1982-06-28 | ||
| JP10991282A JPS592016A (en) | 1982-06-28 | 1982-06-28 | Optical isolator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1253726A true CA1253726A (en) | 1989-05-09 |
Family
ID=26449615
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000430872A Expired CA1253726A (en) | 1982-06-28 | 1983-06-21 | Polarization rotation compensator and optical isolator using the same |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4712880A (en) |
| EP (1) | EP0098730B1 (en) |
| CA (1) | CA1253726A (en) |
| DE (1) | DE3381840D1 (en) |
Families Citing this family (51)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4909612A (en) * | 1986-07-14 | 1990-03-20 | Lightwave Electronics Co. | Optical isolator employing multipass faraday rotation |
| DE3741455A1 (en) * | 1987-12-08 | 1989-06-22 | Standard Elektrik Lorenz Ag | OPTICAL ISOLATOR |
| US4893890A (en) * | 1988-05-04 | 1990-01-16 | Lutes George F | Low-loss, high-isolation, fiber-optic isolator |
| US4974944A (en) * | 1988-07-21 | 1990-12-04 | Hewlett-Packard Company | Optical nonreciprocal device |
| US5033830A (en) * | 1989-10-04 | 1991-07-23 | At&T Bell Laboratories | Polarization independent optical isolator |
| US5052786A (en) * | 1990-03-05 | 1991-10-01 | Massachusetts Institute Of Technology | Broadband faraday isolator |
| US5237445A (en) * | 1990-11-30 | 1993-08-17 | Shimadzu Corporation | Optical isolator |
| EP0512783A3 (en) * | 1991-05-10 | 1993-02-24 | American Telephone And Telegraph Company | Optical isolator with improved stability |
| JPH04371911A (en) * | 1991-06-21 | 1992-12-24 | Hitachi Ltd | Optical isolator and fiber optical amplifier with added rare earth |
| US5191467A (en) * | 1991-07-24 | 1993-03-02 | Kaptron, Inc. | Fiber optic isolater and amplifier |
| US5402509A (en) * | 1991-09-12 | 1995-03-28 | Fujitsu Limited | Optical fiber coupling device including lenses and magnetooptics |
| US5631771A (en) * | 1991-09-19 | 1997-05-20 | Lucent Technologies Inc. | Optical isolator with polarization dispersion and differential transverse deflection correction |
| EP0533398A1 (en) * | 1991-09-19 | 1993-03-24 | AT&T Corp. | Optical isolator with polarization dispersion correction |
| JPH05196890A (en) * | 1992-01-22 | 1993-08-06 | Nec Corp | Optical isolator |
| JP2775547B2 (en) * | 1992-02-17 | 1998-07-16 | 秩父小野田株式会社 | Optical isolator |
| JP2757093B2 (en) * | 1992-04-20 | 1998-05-25 | 富士電気化学株式会社 | Non-polarization dispersion type optical isolator |
| US5768015A (en) * | 1992-12-22 | 1998-06-16 | Telstra Corporation Limited | Optical isolator |
| US5375130A (en) * | 1993-05-13 | 1994-12-20 | Trw Inc. | Azimuthal and radial polarization free-electron laser system |
| US5499307A (en) * | 1993-10-13 | 1996-03-12 | Tdk Corporation | Optical isolator and polarization splitter therefor |
| US5602673A (en) * | 1993-12-29 | 1997-02-11 | Lucent Technologies Inc. | Optical isolator without polarization mode dispersion |
| AUPM774694A0 (en) * | 1994-08-30 | 1994-09-22 | Photonic Technologies Pty Ltd | Split-beam fourier filter |
| US5726801A (en) * | 1994-12-21 | 1998-03-10 | E-Tek Dynamics, Inc. | Reduced optical isolator module for a miniaturized laser diode assembly |
| US5930441A (en) * | 1995-08-30 | 1999-07-27 | Phontonic Technologies Pty Ltd | Split-beam Fourier filter |
| US6239900B1 (en) | 1997-09-19 | 2001-05-29 | Nz Applied Technologies Corp. | Reflective fiber-optic isolator |
| JP3779054B2 (en) * | 1998-01-23 | 2006-05-24 | 富士通株式会社 | Variable optical filter |
| JP3638777B2 (en) | 1998-02-04 | 2005-04-13 | 富士通株式会社 | Method for gain equalization and apparatus and system used to implement the method |
| US6126775A (en) * | 1998-02-06 | 2000-10-03 | Horizon Photonics, Llc | Method of microfabrication |
| US6395126B1 (en) | 1998-02-06 | 2002-05-28 | Horizon Photonics, Inc. | Method of micro-fabrication |
| US6278547B1 (en) * | 1998-05-06 | 2001-08-21 | Hughes Electronics Corporation | Polarization insensitive faraday attenuator |
| US6014244A (en) * | 1998-06-18 | 2000-01-11 | Hewlett-Packard Company | Multi-port optical circulator utilizing imaging lens and correction optical element |
| JP2000066137A (en) * | 1998-08-19 | 2000-03-03 | Fujitsu Ltd | Optical device usable as optical isolator as well as optical amplifier and system including this optical device |
| US6167174A (en) * | 1998-10-27 | 2000-12-26 | Adc Telecommunications, Inc. | Multiple port, fiber optic isolator |
| JP2001094205A (en) * | 1999-09-20 | 2001-04-06 | Sumitomo Electric Ind Ltd | Light emitting device, method of emitting signal light, method of sending signal light, optical communication system and method of determining isolation value |
| US6430323B1 (en) * | 1999-10-20 | 2002-08-06 | Micro-Optics, Inc. | Polarization maintaining optical isolators |
| US6532316B1 (en) | 1999-11-10 | 2003-03-11 | Avanex Corporation | Bi-directional polarization-independent optical isolator |
| US6480331B1 (en) * | 1999-11-10 | 2002-11-12 | Avanex Corporation | Reflection-type polarization-independent optical isolator, optical isolator/amplifier/monitor, and optical system |
| US6532321B1 (en) | 2000-02-16 | 2003-03-11 | Adc Telecommunications, Inc. | Fiber optic isolator for use with multiple-wavelength optical signals |
| US6567578B1 (en) | 2000-02-16 | 2003-05-20 | Adc Telecommunications | Fiber optic device operating at two or more wavelengths |
| TWI316528B (en) * | 2002-01-07 | 2009-11-01 | Cabot Corp | Modified pigment products and black matrixes comprising same |
| JP2003222724A (en) | 2002-01-31 | 2003-08-08 | Hitachi Ltd | 1/4 wavelength plate, optical unit and reflection liquid crystal display using the same |
| JP2004354936A (en) * | 2003-05-30 | 2004-12-16 | Toyo Commun Equip Co Ltd | Laminated wave plate and optical pickup using the same |
| US20070019179A1 (en) | 2004-01-16 | 2007-01-25 | Damian Fiolka | Polarization-modulating optical element |
| US8270077B2 (en) | 2004-01-16 | 2012-09-18 | Carl Zeiss Smt Gmbh | Polarization-modulating optical element |
| KR101295438B1 (en) | 2004-01-16 | 2013-08-09 | 칼 짜이스 에스엠티 게엠베하 | Polarization-modulating optical element |
| US7324280B2 (en) * | 2004-05-25 | 2008-01-29 | Asml Holding N.V. | Apparatus for providing a pattern of polarization |
| US7745777B2 (en) * | 2008-03-11 | 2010-06-29 | Northrop Grumman Space And Mission Systems Corp. | Active imaging system that recaptures and processes a reflected illumination beam |
| CN102377491B (en) * | 2011-10-18 | 2014-11-19 | 武汉光迅科技股份有限公司 | Planar optical waveguide type differential quadrature phase shift keying demodulator |
| CN102401947A (en) * | 2011-11-22 | 2012-04-04 | 华为技术有限公司 | Single-fiber device |
| US20140139911A1 (en) | 2012-11-16 | 2014-05-22 | Electro-Optics Technology, Inc. | Broadband semiconductor faraday effect devices in the infrared |
| CN110231722A (en) * | 2019-05-29 | 2019-09-13 | 华越通信技术(深圳)有限公司 | A kind of optoisolator |
| CN113126210A (en) * | 2020-01-16 | 2021-07-16 | 福州高意通讯有限公司 | Unilateral fiber outlet optical isolator |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1908409B1 (en) * | 1969-02-20 | 1970-06-18 | Zeiss Carl Fa | Device for rotating the direction of oscillation of linearly polarized light by means of crystal-optical components |
| JPS6049297B2 (en) * | 1977-05-31 | 1985-11-01 | 日本電気株式会社 | optical isolator |
| US4129357A (en) * | 1977-08-11 | 1978-12-12 | Nasa | Partial polarizer filter |
| JPS5649517U (en) * | 1979-09-25 | 1981-05-01 | ||
| JPS57100410A (en) * | 1980-12-15 | 1982-06-22 | Fujitsu Ltd | Optical isolator |
-
1983
- 1983-06-21 CA CA000430872A patent/CA1253726A/en not_active Expired
- 1983-06-28 EP EP83303738A patent/EP0098730B1/en not_active Expired - Lifetime
- 1983-06-28 DE DE8383303738T patent/DE3381840D1/en not_active Expired - Lifetime
-
1986
- 1986-08-25 US US06/900,246 patent/US4712880A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| US4712880A (en) | 1987-12-15 |
| EP0098730A3 (en) | 1986-03-19 |
| EP0098730A2 (en) | 1984-01-18 |
| DE3381840D1 (en) | 1990-10-04 |
| EP0098730B1 (en) | 1990-08-29 |
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Legal Events
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| MKEX | Expiry | ||
| MKEX | Expiry |
Effective date: 20060509 |